When Sutter's Mill meteorite split open, out fell seeds of early life

Deborah Netburn

The primordial soup of the early Earth may have been more chemically rich and complex than previously thought, according to new analysis of the Sutter's Mill meteorite, a space rock that exploded over California in 2012.

In a new study published in the Proceedings of the National Academy of Sciences, researchers say they have discovered organic molecules in the Sutter's Mill specimen never before seen in a meteorite, and that those compounds could have played a hand in facilitating molecular evolution, and even life.

Scientists believe the compounds formed when the meteorite's parent asteroid experienced high temperatures as the result of collisions with other asteroids in space.

Since meteorites that slammed into the early Earth also encountered extreme heat conditions -- in the form of volcanoes and asteroid impacts -- the scientists say the early Earth might have been seeded with materials similar to those they found in the Sutter's Mill meteorite.

Just days after chunks of the much-studied space rock fell to the ground, scientists knew it was special. Analysis of its orbit suggested it came from the far reaches of the asteroid belt that lies between Mars and Jupiter -- with its origins closer to Jupiter than Mars.

Early reports noted that it was a rare carbon-rich type of meteorite known as carbonaceous chondrite, which can carry organic materials identical to what are found in amino acids, explained Sandra Pizzarello, a research professor at Arizona State University and lead author of the paper.

Pizzarello was excited to analyze bits of the meteorite in her lab, but her first looks at the space rock didn't find anything particularly interesting.

"It was an absolute disappointment," she said in an interview with The Times.

Then she decided to heat powder extracted from the rock with a bit of water, a procedure she had used to look at other meteorites in the past.

"When I went to look at the results, I didn't see anything I had seen before," she said. "There were these polyethers and polyether-esters, which would be desirable for the formations of cells."

In the paper, Pizzarello and her coauthors conclude that similar compounds could have formed when carbonaceous chondrite meteors landed on the early Earth, where hydrothermal conditions may have facilitated their formation.

"The analysis of meteorites never cease to surprise you," Pizzarello said in a statement.